Many companies have often given a general range of activity: dayhiking, light backpacking, trekking, expedition, etc. I've seen a few listings in which companies would give a weight range like those in Backpacker. However, the truth is that personal conditioning and conditions one will hike in offer a much more realistic viewpoint on which footwear will support which weight.
As a bootfitter, I'm often asked by customers how much weight they should reasonably be able to carry with various shoes and boots. I will offer a general range after I've assessed general foot health, level of overall fitness, experience with varying types of footwear, and the hiker's previous experiences. With all the background information I will often offer an opinion about whether a hiker's intended pack weight is suitable for a certain piece of footwear.
But my personal opinion is that the listed weights i the BP Gear Guyide are extremely generalized and for most experienced hikers who have conditioned their lower extremities are very conservative. I've easily and comfortably carried 45 pounds on boots they list as 25-pounders.